Attachment 373322 Details for Bug 199395 – Updated ChangeLog

[patch] Updated ChangeLog

199395-2.patch (text/plain), 3.72 KB, created by Michael Saboff on 2019-07-02 07:59:10 PDT

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Creator: Michael Saboff

Created: 2019-07-02 07:59:10 PDT

Size: 3.72 KB

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obsolete

>Index: JSTests/ChangeLog
>===================================================================
>--- JSTests/ChangeLog	(revision 247033)
>+++ JSTests/ChangeLog	(working copy)
>@@ -1,3 +1,16 @@
>+2019-07-01  Michael Saboff  <msaboff@apple.com>
>+
>+        Exception from For..of loop assignment eliminates TDZ checks in subsequent code
>+        https://bugs.webkit.org/show_bug.cgi?id=199395
>+
>+        Reviewed by NOBODY (OOPS!).
>+
>+        New regession test.
>+
>+        * stress/for-of-tdz-with-try-catch.js: Added.
>+        (test):
>+        (i.catch):
>+
> 2019-07-01  Ryan Haddad  <ryanhaddad@apple.com>
> 
>         Unreviewed, rolling out r246946.
>Index: JSTests/stress/for-of-tdz-with-try-catch.js
>===================================================================
>--- JSTests/stress/for-of-tdz-with-try-catch.js	(nonexistent)
>+++ JSTests/stress/for-of-tdz-with-try-catch.js	(working copy)
>@@ -0,0 +1,22 @@
>+// This regression test checks that a let in the TDZ state is handled properly
>+// with a for-of in a try as well as the ensuing catch block.
>+
>+function test() {
>+    try {
>+        for ({o} of [, 0])
>+            ;
>+    } catch (e) {
>+        o[0] = 1.5;
>+    }
>+    let o = {
>+    };
>+}
>+
>+for (i = 0; i < 1000; i++) {
>+    try {
>+        test();
>+    } catch(e) {
>+        if (e != "ReferenceError: Cannot access uninitialized variable.")
>+            throw "Expected \"ReferenceError: Cannot access uninitialized variable.\", but got \"" + e +"\"";
>+    }
>+}
>Index: Source/JavaScriptCore/ChangeLog
>===================================================================
>--- Source/JavaScriptCore/ChangeLog	(revision 247033)
>+++ Source/JavaScriptCore/ChangeLog	(working copy)
>@@ -1,3 +1,24 @@
>+2019-07-01  Michael Saboff  <msaboff@apple.com>
>+
>+        Exception from For..of loop destructured assignment eliminates TDZ checks in subsequent code
>+        https://bugs.webkit.org/show_bug.cgi?id=199395
>+
>+        Reviewed by NOBODY (OOPS!).
>+
>+        For destructuring assignmests, the assignment might throw a reference error if
>+        the RHS cannot be coerced.  The current bytecode generated for such assignments
>+        optimizes out the TDZ check after the coercible check.
>+
>+        By saving the current state of the TDZ stack before processing the setting of 
>+        target destructured values and then restoring afterwards, we won't optimize out
>+        later TDZ check(s).
>+
>+        A similar change of saving / restoring the TDZ stack where exceptions might
>+        happen was done for for..in loops in change set r232219.
>+
>+        * bytecompiler/NodesCodegen.cpp:
>+        (JSC::ObjectPatternNode::bindValue const):
>+
> 2019-07-01  Ryan Haddad  <ryanhaddad@apple.com>
> 
>         Unreviewed, rolling out r246946.
>Index: Source/JavaScriptCore/bytecompiler/NodesCodegen.cpp
>===================================================================
>--- Source/JavaScriptCore/bytecompiler/NodesCodegen.cpp	(revision 247033)
>+++ Source/JavaScriptCore/bytecompiler/NodesCodegen.cpp	(working copy)
>@@ -4304,6 +4304,9 @@ void ObjectPatternNode::bindValue(Byteco
>         addMethod = generator.emitGetById(generator.newTemporary(), excludedList.get(), generator.propertyNames().builtinNames().addPrivateName());
>     }
> 
>+    BytecodeGenerator::PreservedTDZStack preservedTDZStack;
>+    generator.preserveTDZStack(preservedTDZStack);
>+
>     for (size_t i = 0; i < m_targetPatterns.size(); i++) {
>         const auto& target = m_targetPatterns[i];
>         if (target.bindingType == BindingType::Element) {
>@@ -4366,6 +4369,8 @@ void ObjectPatternNode::bindValue(Byteco
>             target.pattern->bindValue(generator, result.get());
>         }
>     }
>+
>+    generator.restoreTDZStack(preservedTDZStack);
> }
> 
> void ObjectPatternNode::collectBoundIdentifiers(Vector<Identifier>& identifiers) const

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fpizlo: review+

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